Deskulling apparatus



Oct. 24, 1967 H. A. LONG ETAL 3,348,833

DESKULLING APPARATUS Filed Dec. 9, 1964 5 Sheets-Sheet 1 & m I w o v t Nwe l K I 51 F 1 Q m I l R INVENTORS. HERBERT A. 1.0/10

WILL/AM E. BROWN 4400/5 J. cex/vc/c 5 mgiwagw M1m ATTOR/VEVS.

Oct. 24, 1967 H. A. LONG ETAL 3,348,833

7 I DESKULLING APPARATUS Filed Dec. 9, 1964 5 Sheets-Sheet 5 INVENTORS.HERBERT A. LONG W/LL/AM E. BROWN BY LADD/E J. (RM/67C AUDRNEVS'.

DESKULLING APPARATUS 5 Sheets-Sheet 4 Filed Dec. 9, 1964 ATTORNEVJ.

United States Patent 3,348,833 DESKULLING APPARATUS Herbert A. Long,Belle Vernon, William E. Brown, Centerville, Pa., and Laddie J. Crincic,Belle Vernon, Pa.,

assignors, by mesne assignments, to Blaw-Knox Company, Pittsburgh, Pa.,a corporation of Delaware Filed Dec. 9, 1964, Ser. No. 417,135 11Claims. (Cl. 26636) ABSTRACT OF THE DISCLOSURE Apparatus for deskullinga tiltable steel-making vessel has upwardly directed deskulling teethsupported by a frame pivotally mounted on a horizontal axis. The framenormally holds the teeth in a position to be engaged by the skullprojecting from the vessel when the latter is tilted toward the teeth,but the frame will yield Whenever the pressure of the skull against theteeth exceeds a predetermined value.

In the basic oxygen furnace system of making steel, fuel is not used.Instead, a vessel is charged through its open top with scrap,supplemented with hot metal from a blast furnace. After the requiredfluxes have been added, a jet of practically pure oxygen is directedinto the molten metal through a water-cooled oxygen lance. The requiredconversion temperatures are developed from the exothermic reactions ofoxidation of carbon, silicon and phosphorus resulting from the forcedintroduction of the oxygen. These reactions produce the steeel duringthe blow. Following refinement of the furnace charge into steel in thismanner, the vessel is tilted to pour its molten contents out of its opentop. During pouring, a skull of slag is formed around the vesselopening. This skull continues to build up and obstruct the opening, soit must be removed periodically. Various means have been proposed forbreaking away the skull, i.e. deskulling the vessel, but all of themleave much to be desired. One serious difficulty has been that thevessels drive, motor and supporting structure are damaged during thedeskulling operation, due to the skull striking the deskuller with toomuch force.

It is among the objects of this invention to provide deskullingapparatus which is safe to use, which operates automatically, whichadapts itself to the conditions under which it is operating at any giventime, and which is easy to maintain in satisfactoryoperating condition.

In accordance with this invention, the deskulling apparatus has a framethat is pivotally supported on a horizontal axis beside a tiltablesteel-making vessel that is to be deskulled. The frame supports aplurality of upwardly directed deskulling teeth in front of its pivotalaxis in a row extending lengthwise of it. Preferably, each tooth isprovided with a cap that can easily be replaced when worn. The frame isnormally held in a position where the teeth will be engaged by the skullprojecting from the lip of the vessel in front of the frame when thevessel is tilted toward the teeth. The frame-holding means is adapted toyield whenever the pressure of the skull against the teeth exceeds apredetermined value,

whereby to allow the teeth to be forced downwardly a predetermineddistance. Preferably, from any point within that distance the teeth areraised to their normal position automatically when the skull pressure isremoved. However, if the skull attempts to force the teeth down beyondthat predetermined distance, the rotation of the vessel is stopped andthe frame may be positively rotated to lower the teeth away from theskull to avoid damage.

Patented Oct. 24, 1967 FIG. 2;

FIG. 4 is an exploded front view of one of the deskuller teeth;

FIGS. 5 and 6 are exploded side and rear views, respectively, of thetooth;

FIG. 7 is a plan view, partly in section, of one of the fluid pressurecylinders; and

FIG. 8 is a diagram of the hydraulic system that operates the deskuller.

Referring to the drawings, a typical oxygen converter vessel 1, such asused for making steel in the basic oxygen furnace system, is rigidlymounted in a normally horizontal ring 2 that is provided with trunnions3 that support it in bearings 4. The vessel normally is positioned withits open end up. The vessel is surrounded by a working-floor 6, directlybelow which at one side of the vessel the deskulling apparatus ismounted. This apparatus or deskuller includes a large horizontal shaft 7that is parallel to the axis on which the vessel tilts. One end of theshaft is journaled in a gimbal 8 pivotally mounted on a horizontal axisbetween supports 9 suspended from a beam 10 beneath the floor. The otherend of the shaft is journaled in a bearing 11 supported in a similarmanner. The shaft also is slidable axially in this bearing to allow forthermal expansion.

On the central portion of shaft 7 a deskuller frame is rigidly mounted.Preferably, the frame is rectangular and normally horizontal. It may bemade from two parallel end members 13 through which the shaft extends, acylindrical front member 14 rigidly connected to one of the end membersand slidably connected to the other,

and a back member 15 connecting the rear ends of the end members. Theback member is heavy and serves as a counterweight. Rigidly mounted onthe front member of the frame is a row of deskulling teeth 16 whichextend upwardly from it. As shown in FIG. 2, the upper front edges ofthe teeth are arranged in the general form of an arc and in suchlocation that when the vessel is tilted toward them its lip will clearthe teeth as shown in FIG. 3, but any appreciable build-up of skullaround the lip will strike the teeth.

To enable the teeth to be repaired or replaced readily, it is preferredto construct each tooth from two parts, a cap 18 and an upstanding body19 supporting the cap, each being formed from plates and bars weldedtogether. The lower ends of the tooth bodies surround the front memberof the frame and taper upwardly and slightly forward from it as shown inFIGS. 1, 3 and 5. Each tooth cap is provided with a downwardly openingsocket 20 of a shape to receive and rather loosely fit the upper portionof a tooth body in order that the two members can be connected togetheras a unit. The front wall of the cap is substantially vertical, but itstop is inclined rearwardly and upwardly from the front of the cap.

In order to control the position of the deskuller frame, a pair of arms22 are rigidly connected to shaft 7 near its opposite ends. Preferably,the arms extend downwardly nearly vertically from the shaft while theframe is horizontal. The lower end of each arm is pivotally connected tothe front end of a piston rod 23 that extends back into a fluid pressurecylinder 24. As best shown in FIG. 7, the rear end of the cylinder ismounted in a head 25, from which project integral hollow trunnions 26and 27 that extend through bearings 28 rigidly supported by suitablesupports beneath the floor. The outer ends of draulic system thatoperates the deskuller. The inner end of trunnion 26 communicates insidethe block with the rear end of a pipe 29 that extends along the outsideof the cylinder to its front end. The inner end of the other trunnionopens into the rear end of the cylinder behind the piston 30.

The fluid pressure delivered to the opposite ends of the cylindernormally is the same, but due to the area of the front of the pistonbeing reduced by the piston rod, the pressure against the back of thepiston is greater and therefore the piston normally is held at the frontend of the cylinder to hold the deskuller frame in horizontal position.Whenever the pressure behind the piston is reduced sufficiently, thegreater pressure in front of the piston will force it back in thecylinder and the frame will be tilted to swing the teeth 16 downward asshown in dotted lines in FIG. 3.

This apparatus also is provided with limitswitches for a purpose to bedescribed presently, which are operated as the frame tilts. Preferably,a pair of limit switches 32 and 33 are mounted on a channel 34 extendinglengthwise of each cylinder and attached thereto. A switchactuating bar35 is disposed in each channel and is connected at its front end to thefront end of the piston rod. As the bar is moved back and forth in thechannel 'by the piston rod,v it will actuate the limit switches.

The hydraulic system which operates the deskuller is illustrateddiagrammatically in FIG. 8. It includes a tank 36,.from which hydraulicfluid is pumped by a pair of pumps 37 driven by a motor 38, and to whichthe fluidis returned. The inlets of the pumps are connected by pipes 39to the tank, while their outlets are connected through check valves 41to a common pipe 42 that is connected by a delivery pipe 43 to asolenoidoperated pilot controlled directional valve 44. While in oneposition, this valve connects the delivery pipe with a check valve 46that is provided with solenoid-operated pilot controlled means 47energized by limit switch 33 for opening the valve under certainconditions to allow reverse flow through it. The outlet of this checkvalve is connected with a common pipe 48 that delivers the fluid to thehollow trunnions 27 connected with the rear ends of the two cylinders.Pipe 48 also is connected through pipes 49 with adjustable relief valves50, the outlets of which are connected through pipes 51 and much lowerpressure relief valves 52 with the tank.

Common pipe 42 also is connected by pipes 54 with the hollow trunnions26 that communicate through pipes 29 with the front or rod ends of thecylinders. Pipes 54 also are connected by electrically adjustable reliefvalves 55, controlled by limit switches 32, with the tank. There also isa check valve 56 between each pipe 54 and the adjacent pipe 51 for apurpose that will be explained later.

When the directional valve 44 is shifted to its opposite position, itcloses delivery pipe 43 and connects the reversible check valve 46 witha relief valve 58 in a pipe 59 leading back to the tank. Valve 58 opensat a pressure just high enough to maintain sufficient fluid pressure inthe system to operate the necessary controls.

Assuming that the deskuller teeth are in their lowest position, thisapparatus is set in operation by closing a switch in a suitable electriccircuit which will energize one of the solenoids connected with thedirectional valve 44 to cause it to shift from its right-hand positionto its left-hand position as shown. Simultaneously, the circuit willstart motor 38 to operate the pumps and energize the solenoids thatcontrol relief valves 55 to adjust those valves to their high pressuresetting so that a high fluid pressure, such as 500 pounds p.s.i., can bebuilt up in the system. Fluid then will be pumped out of the tank anddelivered through pipes 43 and 54 to the opposite ends of cylinders 24.This will cause the pistons 30 to be moved forward to rotate thedeskuller frame and 4 thereby swing the teeth up to operating position.As the pistons reach the front ends of the cylinders, limit switches 32will open to cause relief valves 55 to open at a much lower pressure,such as pounds p.s.i., but the high pressure in the rear or blind endsof the cylinders will be maintainedbecause check valve 46 will preventflow.

of fluid therefrom back toward the pumps.

The converter vessel then is tilted. over toward the deskuller teeth tostrike the skull around the lip of the vessel against them. If thatbreaks the skull away from the vessel, that is all that is necessary andthe vessel then can be returned to upright position. On the other hand,if the skull does not break away upon engagement with the teeth, itsdownward pressure on the teeth will cause the pivoted frame to force thepistons back against the fluid in the cylinder until the pressuretherein builds up sufficiently to open relief valves 50, which areadjustable for opening at any desired pressure above the high setting ofrelief valves 55,'such as above SOOpounds p.s.i. It has been foundsuitable to have valves 50 open when the fluid pressure thereon reachesabout 1800 p.s.i. Opening of the relief valves 50 will allow the teethto be pushed down by the skull to prevent breakage of any of theequipment. It will be seen that the maximum resisting force of thedeskuller against the skull on the top of the vessel is determined bythe setting of relief valves 50. Since the vessel is likely to push thepistons back in the cylinders faster than fluid can be pumped into theirfront ends, cavitationin the front ends is prevented by fluid beingexhausted from relief valves 50. This fluid will flow through checkvalves 56 and maintain the front ends of the cylinder full.

As soon as the deskuller teeth start to move down, the switch bars 35close limit switches 32 so that relief valves 55 will be returned totheir high pressure setting and high pump pressure again will beavailable for the rear ends of the cylinders. If the skull breaks awaybefore the teeth have moved down a predetermined short distance, such as8 or 10 inches for example, the teeth immediately will be swung orbounced back up to their upright position by the high fluid pressuredelivered by the pumps behind the pistons.

It may happen, however, that the skull does not break away from thevessel while the teeth are moving down the short distance justmentioned, so to prevent damage and to permit another attempt atbreaking the skull the teeth are, pulled downwardly away from the skull.This happens as soon as the switch bars are moved back along thecylinders far enough to close limit switches 33. Through a suitableelectrical control circuit, closing of these switches stops the tiltingof the vessel and causes the directional valve 44 to shift to the rightin order to connect drain pipe 59 with check .valve 46. Limit switches33 also operate the control means 47 that-causes check valve 46 to openso that there can be reverse flow through it. The fluid pressure behindthe pistons thus is connected with drain, so the higher fluid pressurein the front ends of the cylinders moves the pistons rearwardly therein.When the pistons reach their rearmost position in the cylinders, theswitch bars 35 close a third set of limit switches 61 attached tochannels 34 to turn the pump motor off. The vessel then can be tiltedback to upright position and then the deskuller teeth can be swung backup to their operating. position so that the cycle can be repeated.

It will be seen that withthis apparatus deskulling can be effected withsmall likelihood of either the vessel or the deskulling apparatus beingdamaged, because as soon as excessive pressure starts to develop betweenthe skull and the deskuller teeth, the teeth first yield downwardly andthen, if the pressure is not relieved, they are pulled away from theskull. The construction of the teeth permits them to be maintained ingood condition with little effort and expense.

We claim:

1. Apparatus for deskulling a tiltable steel-making vessel used in abasic oxygen furnace system, said apparatus comprising a frame, meanspivotally supporting the frame on .a horizontal axis, a plurality ofupwardly directed deskulling teeth supported by the frame in front ofsaid axis in a row extending lengthwise of it, each of said teethincluding a tooth body rigidly mounted on the front of the frame and atooth cap provided with a downwardly opening socket receiving the upperend portion of said body to support the cap, and means connected withthe frame and normally holding it in a position where said teeth will beengaged by the skull projecting from the lip of a vessel in front of theframe when the vessel is tilted toward the teeth, said means beingadapted to yield whenever the pressure of the skull against the teethexceeds a predetermined value to allow the teeth to be forceddownwardly.

2. Apparatus for deskulling a tiltable steel-making vessel used in abasic oxygen furnace system, said apparatus comprising a frame, meanspivotally supporting the frame on a horizontal axis, a plurality ofupwardly directed deskulling teeth supported by the frame in front ofsaid axis in a row extending lengthwise of it, means connected with theframe and normally holding it in a position where said teeth will beengaged by the skull projecting from the lip of a vessel in front of theframe when the vessel is tilted toward the teeth, said means beingadapted to yield whenever the pressure of the skull against the teethexceeds a predetermined value to allow the teeth to be forced downwardlya predetermined distance, said means also being adapted to raise theteeth to their normal position from any point within said distance whensaid pressureis removed, and means op erative if the skull attempts toforce the teeth down more than said predetermined distance for rotatingthe frame to lower the teeth away from the skull.

3. Apparatus for deskulling a tiltable steel-making vessel used in abasic oxygen furnace system, said apparatus comprising a frame, meanspivotally supporting the frame on a horizontal axis, a plurality ofupwardly directed deskulling teeth supported by the frame in front ofsaid axis in a row extending lengthwise of it, an arm having one endconnected with the frame for tilting the frame, fluid pressure meansoperatively connected with the opposite end of the arm for normallyholding it and the frame in a position where said teeth will be engagedby the skull projecting from the lip of a vessel in front of the framewhen the vessel is tilted toward the teeth, a relief valve connectedwith said fluid pressure means and adapted to be opened whenever thepressure of the skull against the teeth exceeds a predetermined value toallow them to be forced down, the fluid pressure means being effectiveto swing said arm to raise the teeth to their normal position from anypoint above a predetermined point whenever said skull pressure isremoved, and means for reversing said fluid pressure means if the skullattempts to force the teeth down past said predetermined point, wherebyto tilt the frame in a direction to lower the teeth away from the skull.

4. Apparatus for deskulling a tiltable steel-making vessel used in abasic oxygen furnace system, said apparatus comprising a frame, meanspivotally supporting the frame on a horizontal axis, a plurality ofupwardly directed deskulling teeth supported by the frame in front ofsaid axis in a row extending lengthwise of it, an arm having one endconnected with the frame for tilting the frame, a hydraulic cylinder andpiston connected with the opposite end of the arm, hydraulic pressurefluid in one end of the cylinder normally holding the arm and frame in aposition where said teeth will be engaged by the skull projecting fromthe lip of a vessel in front of the frame when the vessel is tiltedtoward the teeth, a relief valve having an inlet connected with said oneend of the cylinder and adapted to be opened by said pressure fluidwhenever the pressure of the skull against the teeth exceeds apredetermined value to allow them to be forced down a predetermineddistance, means for replenishing said pressure fluid in said cylinder toraise the teeth to their normal position from any point within saiddistance when said skull pressure is removed, and means independent ofsaid relief valve for releasing fluid pressure from said one end of thecylinder while fluid pressure is applied to the opposite end of thecylinder if the skull attempts to force the teeth down more than saidpredetermined distance, whereby to tilt the frame for lowering the teethaway from the skull.

'5. Deskulling apparatus according to claim 4, including a second reliefvalve that opens at a lower pressure than said first-mentioned reliefvalve, and means connecting the outlet of said first-mentioned valvewith said opposite end of the cylinder and said second relief valve.

6. (Deskulling apparatus according to claim 4, in which said fluidpressure releasing means includes a check valve normally trapping fluidin said one end of the cylinder, and means for opening said check valveto permit reverse flow therethrough when the skull attempts to forcesaid teeth down more than said predetermined distance.

7. Deskulling apparatus according to claim 6, in which said check valveopening means is electrically operated by means including a limit switchthat is actuated when said teeth start to move down more than saidpredetermined distance.

8. Deskulling apparatus according to claim 4, in which said fluidpressure releasing means includes a check valve normally trapping fluidin said one end of the cylinder, a directional valve normally connectingsaid replenishing means with the check valve, and means for opening saidcheck valve to permit reverse flow therethrough and for shifting saiddirectional valve to disconnect said replenishing means from the checkvalve and to connect said reverse flow with drain.

9. Apparatus for deskulling a tiltable steel-making vessel used in abasic oxygen furnace system, said apparatus comprising a frame, meanspivotally supporting the frame on a horizontal axis, a plurality ofupwardly directed deskulling teeth supported by the frame in front ofsaid axis in a row extending lengthwise of it, an arm having one endconnected with the frame for tilting the frame, a hydraulic cylinder andpiston connected with the opposite end of the arm in a position to swingthe teeth upward when the piston and blind end of the cylinder areforced away from each other, a hydraulic pump having an outlet connectedwith the opposite ends of said cylinder for normally holding said armand frame in a position where said teeth will be engaged by the skullprojecting from the lip of a vessel in front of the frame when thevessel is tilted toward the teeth, a check valve normally trapping fluidin the blind end of the cylinder, a relief valve connected to the pumpoutlet adapted to be opened at a predetermined fluid pressure, saidrelief valve being adjustable to open at a much higher fluid pres-sure,a second relief valve having an inlet connected with the blind end ofthe cylinder and adapted to be opened by pressure fluid therein wheneverthe pressure of the skull against the teeth exceeds a predeterminedvalue to allow the teeth to be forced down a predetermined distance,means for adjusting said firstmentioned relief valve to open at saidhigher pressure when said teeth start to move downward, and means foropening said check valve to permit reverse flow therethrough if theskull attempts to force said teeth down more than said predeterminedamount, whereby the frame will be tilted in a direction to lower theteeth from the skull.

10. Apparatus for deskulling a tiltable steel-making vessel used in abasic oxygen furnace system, said apparatus comprising a frame, meanspivotally supporting the frame on a horizontal axis, a plurality ofupwardly directed deskulling teeth supported by the frame in front ofsaid axis in a row extending lengthwise of it, an arm having one endconnected with the frame for tilting the frame, a hydraulic cylinder andpiston connected with the opposite end of the arm, means for deliveringequal fiuid pressure to both ends of the cylinder so that the piston ismoved toward the rod end of the cylinder to hold said arm and frame in aposition where said teeth will be engaged by the skull projecting fromthe lip of a vessel in front of the frame when the vessel is tiltedtoward the teeth, a check valve normally preventing flow of fluid fromthe blind end of the cylinder back toward said source, a relief valvehaving an inlet connected with the blind end of the cylinder an'dadaptedto be opened by fluid pressure therein whenever the pressure of theskull against said teeth pushes the piston to-- ward the blind end ofthe cylinder with sufficient force, and means for opening said checkvalve to permit reverse flow therethrough if the piston is forced morethan a predetermined distance toward the blind'end of the cylinder,whereby the fluid pressure in the rod end of the cylinder will move thepiston closer to said blind end to tilt the frame in a directionthattwill lower the teeth from the skull.

11. Apparatus for desku'lling a tiltable steel-making vessel used in abasic oxygen furnace system, said apparatus comprising a frame, meanspivotally supporting '8 the frame on a horizontal axis, a plurality ,ofupwardly directed deskulling teeth supported by the frame in front ofsaid axis in a row extending lengthwise of it, each of said teethincluding an upright front plate and a top plate joined at its upper endto the upper end of the front plate, and means connected with the frameand normally holding it in a position where said teeth will be engagedby the skull projecting from the lip of a vessel in front of the framewhen the vessel is tilted toward the teeth, said means being adapted toyield whenever the pressure of the skull against the teeth exceeds apredetermined value to allow the teeth to be forced downwardly.

References Cited UNITED STATES PATENTS 1,783,373 1 12/1920 BOI'tOn 241239 'X' 2,297,604 9/1942 Baternan et al. s 241-239 3,197,187 7/1965Lakin et al. 26636 FOREIGN PATENTS 1,358,565 4/1964 France.

I. SPENCER OVERHOLS'ER, Primary Examiner. WILLIAM J. STEPHENSON,Examiner.

E. MAR, Assistant Examiner.

1. APPARATUS FOR DESKULLING A TILTABLE STEEL-MAKING VESSEL USED IN ABASIC OXYGEN FURNACE SYSTEM, AND APPARATUS COMPRISING A FRAME, MEANSPIVOTALLY SUPPORTING THE FRAME ON A HORIZONTAL AXIS, A PLURALITY OFUPWARDLY DIRECTED DESKULLING TEETH SUPPORTED BY THE FRAME IN FRONT OFSAID AXIS IN A ROW EXTENDING LENGTHWISE OF IT, EACH OF SAID TEETHINCLUDING A TOOGH BODY RIGIDLY MOUNTED ON THE FRONT OF THE FRAME AND ATOOTH CAP PROVIDED WITH A DOWNWARDLY OPENING SOCKET RECEIVING THE UPPEREND PORTION OF SAID BODY TO SUPPORT THE CAP, AND MEANS CONNECTED WITHTHE FRAME AND NORMALLY HOLDING IT IN A POSITION WHERE SAID TEETH WILL BEENGAGED BY THE SKULL PROJECTING FROM THE LIP OF A VESSEL IN FRONT OF THEFRAME WHEN THE VESSEL IS TILTED TOWARD THE TEETH, SAID MEANS BEINGADAPTED TO YIELD WHENEVER THE PRESSURE OF THE SKULL AGAINST THE TEETHEXCEEDS A PREDETERMINED VALUE TO ALLOW THE TEETH TO BE FORCEDDOWNWARDLY.